Harlan Kleinstock was a member of Magneto's Acolytes, along with his twin brother Sven and his other brother Eric. He & Sven were able to merge together into one super being with enhanced strength and durability

Harlan Kleinstock is the twin brother of Sven Kleinstock and normal brother of Eric Kleinstock. They were part of the mutant supremecist team that devoted themselves to Magneto and his ideals, the Acolytes. Eric was killed in battle shortly after being introduced, but Harlan & Sven lived to survive even the destruction of Asteroid M and the Genoshan Sentinel Genocide, catalyzed by Cassandra Nova. It is presumed that they were among the thousands of mutants to lose their powers post decimation, however, they have gone AWOL, so this suspicion has not yet been confirmed.